This invention relates to a protective suit.
More particularly, the invention relates to a protective suit of a type suitable for diving, gas protection, rescue work and similar applications.
Still more particularly, the invention relates to such a suit which is worn in inflated condition, that is, at internal air pressure which is preferably in excess of ambient pressure.
Various types of materials are used for diving suits, depending on the nature and extent of the diving.
There are both dry and wet diving suits. The former are made of, for instance, rubber-coated textile, whereas wet suits are made of expanded neoprene or natural rubber mainly on the outside, and are reinforced by tricot on the inside.
Two types of variable-volume dry suits are known, one made of dry suit material and the other of wet suit material. With both types of suits underwear must be used for thermal insulation of the diver. Further thermal protection of the diver is achieved by admitting air into the suit during the diving descent, in such a quantity that the inner pressure in the suit as a rule becomes greater than or equal to the surrounding water pressure. The buoyancy of the diver is balanced by lead weights (e.g. a weight belt).
As regards the present variable volume suits, that part of the suit that may be thus put under overpressure is terminated at the neck. Therefore the head region does not have any thermal protection other than that which is afforded by the ordinary wet suit protection.
The thermal insulation of the head and the area around the head may, accordingly, be considered inadequate. There has been no lack of ideas for the solution of this problem, but no practical solution has heretofore been proposed which combines easy applicability, sealing against the outer and inner surroundings, and effective thermal insulation of the head region.
Attempts have been made to employ suit hoods (head hoods) made from expanded neoprene or latex. The drawback of these hood types is that they fit closely to the head and neck, thus providing only a limited thermal protection. Besides, the expanded material becomes increasingly compressed as the diver goes deeper, the result being a reduction of the thermal insulation in case of diving to greater depths.
Efforts have been made to avoid these problems by blowing air into the hood, which for this purpose has been furnished with a lip seal in the face opening instead of the usual neck seal. However, it appears impossible to produce a face seal that may be said to be practically serviceable, as the design does not allow a sufficient overpressure in the suit.